diff --git a/pkgs/development/libraries/qrupdate/default.nix b/pkgs/development/libraries/qrupdate/default.nix
index 90d4cb45ce2..b941021cb68 100644
--- a/pkgs/development/libraries/qrupdate/default.nix
+++ b/pkgs/development/libraries/qrupdate/default.nix
@@ -25,10 +25,10 @@ stdenv.mkDerivation rec {
       "BLAS=-L${blas}/lib -lblas"
       "PREFIX=${placeholder "out"}"
       ${stdenv.lib.optionalString blas.isILP64
-      # Use their FFLAGS along with `-fdefault-integer-8`. If another
-      # application intends to use arpack, it should add this to it's FFLAGS as
-      # well. Otherwise (e.g): https://savannah.gnu.org/bugs/?50339
-      "FFLAGS=-fimplicit-none -O3 -funroll-loops -fdefault-integer-8"
+      # If another application intends to use qrupdate compiled with blas with
+      # 64 bit support, it should add this to it's FFLAGS as well. See (e.g):
+      # https://savannah.gnu.org/bugs/?50339
+      "FFLAGS=-fdefault-integer-8"
       }
     )
   '';